JP4131734B2 - Washing wastewater treatment equipment - Google Patents

Description

  The present invention relates to a treatment apparatus for washing wastewater and washing wastewater, and more particularly to a treatment apparatus for washing wastewater and washing wastewater discharged from nuclear facilities. The present invention also relates to a technique that can be applied to a wastewater treatment apparatus when the installation area is limited, such as facility modification.

  For example, laundry wastewater or washing wastewater (hereinafter referred to as laundry wastewater) discharged from nuclear facilities contains trace amounts of radioactive substances in addition to organic substances such as detergents, fabric fibers, fats, and carbohydrates. It is. These substances must be removed and detoxified in order to meet the release limits.

  Conventional treatment methods for detoxifying laundry wastewater include treatment methods that add powdered activated carbon or powder ion exchange resin to laundry wastewater, adsorb organic substances and radioactive substances contained in the wastewater, and then filter them with a precoat filter. There is a treatment method in which the solution is directly filtered through an ultrafiltration membrane or a reverse osmosis membrane, and the concentrated solution is evaporated and concentrated. In recent years, an attempt has been made to add ozone to laundry wastewater and oxidatively decompose organic substances therein.

  However, the processing method of filtering with a precoat filter has a problem that the amount of radioactive waste increases due to the added powdered activated carbon or powder ion exchange resin. In addition, the method of directly filtering through an ultrafiltration membrane or reverse osmosis membrane and evaporating and concentrating the concentrated liquid consumes energy because the evaporative concentrated liquid contains radioactive substances together with a considerable amount of non-radioactive salts in the detergent. There is a problem that not only the amount is large but also the amount of radioactive waste is increased, resulting in high processing costs.

  Furthermore, the method of adding ozone is effective in decomposing the surfactant contained in the detergent, but the amount of ozone consumption is very large. Since ozone is a relatively expensive oxidizer, there is a disadvantage that the equipment cost and the operation cost are very high and it is very uneconomical.

  Accordingly, an object of the present invention is to provide a treatment method and apparatus capable of effectively treating laundry wastewater from a nuclear facility and greatly reducing the amount of radioactive waste with low equipment and operating costs. That is.

In order to achieve this object, a wastewater treatment apparatus according to the present invention described in claim 1 is provided in a biological treatment tank for aeration and mixing of laundry wastewater from a nuclear facility with activated sludge, and the biological treatment tank. , A microfiltration membrane for solid-liquid separation of the liquid mixture obtained by the aeration mixing, a first aeration means provided immediately below the microfiltration membrane for the aeration mixing, and generated bubbles in the microfiltration membrane Second aeration means provided at a position in the biological treatment tank that does not contact, a membrane filtration water tank that receives membrane filtrate from the microfiltration membrane, and an excess sludge tank that receives excess sludge in the biological treatment tank. A laundry wastewater treatment apparatus is provided.

  As in the present invention according to claim 2, the laundry wastewater treatment apparatus is connected to a circulation pump that draws out a part of the excess sludge from the excess sludge tank and returns it to the excess sludge tank, and the circulation pump. It is preferable to further include an ozone reaction tank disposed on the downstream side, and the circulation pump communicates with an ozone source on the upstream side.

  In addition, as described in claim 3, it is preferable to add about 0.04 to 0.08 kg of ozone per kg of dried excess sludge from the ozone source to the excess sludge.

  In addition, as in the present invention according to claim 4, the laundry wastewater treatment apparatus includes a mixing tank that mixes the received cleaning wastewater with a desorption liquid and supplies the mixed wastewater to the biological treatment tank, and the biological treatment tank. A circulation pump for extracting a part of the activated sludge and returning it to the mixing tank; and an ozone reaction tank arranged on the downstream side in communication with the circulation pump, the circulation pump serving as an ozone source on the upstream side It is preferable to contact.

  In this case, as described in claim 5, it is preferable to add about 0.04 to 0.1 kg of ozone per kg of dry sludge from the ozone source to a part of the activated sludge.

  As described in claim 6, hydrogen peroxide water may be added to the surplus sludge tank.

  In that case, as described in claim 7, the injection amount of the hydrogen peroxide solution is preferably about 0.05 to 0.1 kg per 1 kg of the dried excess sludge.

According to the laundry wastewater treatment apparatus of the first aspect of the present invention, the laundry wastewater discharged from the nuclear facility is aerated and mixed with activated sludge, and the obtained mixed liquid is solid-liquid separated by a microfiltration membrane. As a result, it is possible to effectively treat the washing waste water from the nuclear facility, to greatly reduce the radioactive waste, and to reduce the equipment cost and operation cost.
According to the present invention as set forth in claim 1, the wastewater treatment apparatus is provided in the biological treatment tank for aeration mixing of the wastewater from the nuclear facility with activated sludge, and the aeration mixing A microfiltration membrane for solid-liquid separation of the liquid mixture obtained by the above, a first aeration means provided immediately below the microfiltration membrane for the aeration mixing, and the organism in which the generated bubbles do not contact the microfiltration membrane Since it comprises a second aeration means provided at a position in the treatment tank, a membrane filtration water tank that receives membrane filtrate from the microfiltration membrane, and an excess sludge tank that receives excess sludge in the biological treatment tank, By providing two aeration means, not only can the over-aeration and sludge sedimentation in the biological treatment tank be prevented, but also the mechanical deterioration due to membrane vibration due to clogging and over-aeration of the microfiltration membrane can be reduced, thereby improving precision. Life of filtration membrane It is possible to extend the. Moreover, not only the treatment performance within the washing drainage inflow time but also the self-digestion of the sludge in the time zone when it does not flow can be minimized, and the deterioration of the treated water quality can be avoided.

  In addition, as in the laundry wastewater treatment apparatus according to claim 2, a circulation pump that draws a part of the excess sludge from the excess sludge tank and returns it to the excess sludge tank, and communicates with the circulation pump on the downstream side. And a circulating pump that communicates with an ozone source on the upstream side of the circulating pump, and oxidatively decomposes about 70 to 90% of the excess sludge into carbon dioxide gas and water. it can.

  In the laundry wastewater treatment apparatus according to claim 2, as in the present invention of claim 3, about 0.04 to 0.08 kg of ozone per 1 kg of excess dry sludge is added to the excess sludge from an ozone source. Then, it is possible to prevent in advance problems that the excess sludge is insufficiently oxidized and decomposed and the amount of decrease in excess sludge is reduced, or ozone is excessive and an unreacted ozone treatment device is required. .

  Further, as in the present invention according to claim 4, the received washing wastewater is mixed with the desorption liquid and supplied to the biological treatment tank, and a part of the activated sludge is extracted from the biological treatment tank. A circulation pump that returns to the mixing tank; and an ozone reaction tank that communicates with the circulation pump and is disposed downstream of the circulation pump. The circulation pump communicates with an ozone source on the upstream side of the circulation pump. It is suitable for a treatment that occurs only during the day, and even if unreacted ozone is present in the ozone reaction tank, it can be used for oxidation of organic matter in the laundry wastewater in the mixing tank. In this case, as described in claim 5, when approximately 0.04 to 0.1 kg of ozone per kg of dry sludge is added from the ozone source to a part of the activated sludge, oxidation of excess sludge is performed as in claim 3. This is convenient because problems such as insufficient decomposition and a decrease in excess sludge, or excessive ozone and a need for an unreacted ozone treatment device can be prevented in advance.

  As in the present invention described in claim 6, by adding hydrogen peroxide water to the excess sludge tank, about 70 to 90% of the excess sludge can be oxidized and decomposed into carbon dioxide gas and water. If the amount of hydrogen peroxide water injected is about 0.05 to 0.1 kg per 1 kg of dry surplus sludge as in the present invention according to claim 7, the surplus sludge is not sufficiently oxidized and decomposed. There is no reduction in the amount of sludge reduction, excessive hydrogen peroxide solution, and no need for a reducing agent for unreacted hydrogen peroxide solution.

  Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or corresponding parts. Further, as will be understood from the following description, the present invention is not limited to this embodiment, and various modifications are possible.

(Embodiment 1)
Figure 1 shows an embodiment of a treatment facility or processing system for carrying out the processing method. In FIG. 1, laundry wastewater 1 first flows into a biological treatment tank (which may be called a membrane separation tank) 2. A floating activated sludge floc is held in the biological treatment tank 2, and a flat membrane-like separation membrane 3 made of a membrane module is immersed therein. As a method for holding the activated sludge, there is a method of using a particulate carrier and a fibrous carrier, without these various carriers in the form of a good optimal implementation, it is preferable to use a floating activated sludge flocs. The reason for not using the carrier is that the inside of the activated sludge deposited and grown in a layered manner on the carrier surface is likely to be in an anaerobic state, and the separation membrane 3 is blocked when it peels off.

  Normally, washing wastewater in nuclear facilities is generated by daytime operations, and there are many outflow patterns that do not occur at night, and the wastewater flow rate and water quality fluctuate drastically. It can be configured to once flow into the mixing tank, where the flow rate and water quality are equalized and then flow into the biological treatment tank 2.

  In this embodiment, the separation membrane 3 is a microfiltration membrane having a pore diameter of 0.4 μm, and has a function of allowing water to pass but not allowing activated sludge or fine particles to pass. An aeration pipe (aeration means) 6 communicating with an external blower (not shown) is installed in the biological treatment tank 2 preferably below the separation membrane 3 at the bottom, and air is passed through this aeration pipe 6. 5 is supplied into the biological treatment tank 2. The air 5 mixes and aerates the activated sludge and the washing waste water, and the surface of the separation membrane 3 is bubble-washed to prevent the activated sludge from adhering to the separation membrane 3 and blocking the pores. There is a water level difference between the biological treatment tank 2 and the membrane filtration water tank 7 disposed in the vicinity thereof, and the clear membrane filtrate 4 that has passed through the separation membrane 3 due to this water level difference is the membrane filtration water tank 7. And discharged as treated water 8. Note that the membrane filtrate 4 may be pumped into the membrane filtrate tank 7.

  On the other hand, the activated sludge increased with the decomposition of the organic components in the washing wastewater is extracted from the biological treatment tank 2 as surplus sludge 9 and introduced into the surplus sludge tank 10, and from here to the dewatering machine 12 by the surplus sludge pump 11. The dehydrated cake 12 is dehydrated by the dehydrator 12. The desorbed liquid 14 generated at this time is returned to the biological treatment tank 2. When the laundry wastewater is wastewater from a nuclear facility, a trace amount of radionuclide contained therein is retained in the activated sludge floc and is contained in the dewatered cake 13 and removed together with the excess sludge 9. Incidentally, the decontamination coefficient (radioactivity concentration in laundry wastewater / radioactivity concentration ratio in treated water) is 10-20.

  This activated sludge floc was initially introduced with sewage sludge and sludge used in industrial wastewater treatment as seed sludge, adapted to laundry drainage while adding ammonium salt and phosphate as nutrient sources, and the activated sludge concentration is Grow until reaching about 6000-10000 mg / L. Thereafter, the addition of the nutrient source is stopped, and the treatment is preferably performed in an oligotrophic state of only a small amount of nitrogen (N) and phosphorus (P) contained in the laundry wastewater. As a result, the amount of activated sludge in the biological treatment tank 2 is increased, and as a result, the amount of surplus activated sludge is reduced. Therefore, the amount of dehydrated cake 13 can be reduced.

  Furthermore, in order to reuse the treated water 8 as washing water, it is necessary to reduce the increase in the amount of salts in the treated water 8 due to the addition of salts as a nutrient source. This is because an increase in salt causes yellowing of the laundry. By stopping the addition of the nutrient source as described above, the reuse rate of the treated water 8 can be 50 to 70%.

(Embodiment 2)
As can be seen from Figure 2 showing a second embodiment of the processing equipment for carrying out the processing method, the second embodiment, the circulating pump 15 to the first embodiment of FIG. 1, the ozone reaction vessel as an ozone source 20. The configuration is substantially the same as that of the first embodiment except that an oxygen enricher 17 and an ozone generator 18 and piping related thereto are added. In the second embodiment, a part of the excess sludge is extracted from the excess sludge tank 10 by the circulation pump 15 and introduced into the ozone reaction tank 20. At that time, ozone 19 generated by the oxygen enricher 17 and the ozone generator 18 from the dry air 16 is mixed into the suction side of the circulation pump 15, dissolved in the ozone reaction tank 20, and then returned to the excess sludge tank 10. . As a result, about 70 to 90% of the excess sludge is oxidized and decomposed into carbon dioxide and water.

  The amount of ozone 19 injected is preferably about 0.04 to 0.08 kg per 1 kg of dry surplus sludge. If it is less than about 0.04 kg, the oxidative decomposition of surplus sludge becomes insufficient, the amount of decrease of surplus sludge decreases, the scale of the dehydrator 12 increases, and the amount of dehydrated cake 13 increases. If it exceeds about 0.08 kg, the ozone 19 becomes excessive, and not only the device scales of the oxygen enricher 17 and the ozone generator 18 are increased, but also an unreacted ozone treatment device is required.

(Embodiment 3)
Figure 3 shows a third embodiment of the treatment facility for carrying out the processing method. In Embodiment 3 of FIG. 3, the mixing tank or the adjustment tank 21 is provided as a pre-process of the biological treatment tank 2, and while the washing waste water 1 and the detachment liquid 14 are introduced into this mixing tank 21, the biological tank The activated sludge in the treatment tank 2 is extracted by the circulation pump 15 and introduced through the ozone reaction tank 20. At that time, the ozone 19 generated by the oxygen enricher 17 and the ozone generator 18 from the dry air 16 is mixed into the suction side of the circulation pump 15 as in the embodiment of FIG.

  In Embodiment 3 of FIG. 3, it is preferable that the injection amount of ozone 19 is about 0.04 to 0.1 kg per 1 kg of dry sludge. If it is less than about 0.04 kg, the oxidative decomposition of surplus sludge becomes insufficient, the amount of surplus sludge decreases, the scale of the dehydrator 12 increases, and the amount of dewatered cake 13 increases. Further, when the injection amount is more than about 0.1 kg, the ozone 19 becomes excessive, and not only the device scale of the oxygen enricher 17 and the ozone generator 18 is increased, but also an unreacted ozone treatment device is required. The reason why a slightly larger amount of ozone is introduced than in the embodiment of FIG. 2 is that unreacted ozone can be used in the ozone reaction tank 20 for oxidation of organic matter in the laundry wastewater 1 in the mixing tank 21. .

(Embodiment 4)
Fourth implementation shown in FIG. 4, in addition to hydrogen peroxide 22 is added to the excess sludge tank 10 is in the form 1 substantially the same configuration of the embodiment of Figure 1. By adding the hydrogen peroxide solution 22 to the excess sludge tank 10, about 70 to 90% of the excess sludge is oxidized and decomposed into carbon dioxide gas and water.

  The injection amount of the hydrogen peroxide solution 22 is preferably about 0.05 to 0.1 kg per 1 kg of dried excess sludge. If the amount is less than about 0.05 kg, the oxidative decomposition of the excess sludge becomes insufficient, the amount of reduction of the excess sludge decreases, the scale of the dehydrator 12 increases, and the amount of the dehydrated cake 13 increases. If the injection amount is more than about 0.1 kg, the hydrogen peroxide solution 22 becomes excessive, which is not economical, and a reducing agent for the unreacted hydrogen peroxide solution 22 is required.

( Reference Example 1)
Washing wastewater discharged from the nuclear facility was treated with the treatment facility shown in FIG. Water washing wastewater, BOD180mg / L, COD125mg / L , SS70mg / L, nitrogen (N) 4mg / L, phosphorus (P) 0.5mg / L, conductivity of 500 .mu.S / cm, the activity concentration 2 × 10 ^-3 Bq / mL. The biological treatment tank had a BOD volume load of 0.8 kg / m ³ · d, a COD volume load of 0.6 kg / m ³ · d, and an activated sludge concentration of about 10,000 mg / L. Here, L is liters. Table 1 shows the processing results at this time. As can be seen from Table 1, the quality of the treated water sufficiently satisfied the discharge regulation value (30 mg / L or less). Moreover, it was confirmed that even if the treated water is reused as washing water, the laundry does not turn yellow.

( Reference Examples 2, 3 and 4)
Table 1 shows the results of treating the same laundry wastewater as used in Reference Example 1 with the treatment facilities shown in FIGS.

  In the first to fourth embodiments described above, the air 5 supplied from the blower is jetted from the diffuser tube 6 to become bubbles, and the surface of the separation membrane 3 is washed. Prevents the decline. However, when the wastewater flow rate is high and the pollutant (BOD, COD) concentration is low, the air supply amount to the biological treatment tank 2 becomes excessive (over-aeration) than the air amount necessary for BOD decomposition. As a result, the activated sludge flocs can be subdivided to facilitate clogging of the separation membrane 3, and there is a possibility of causing a vicious cycle of deterioration of treated water quality due to self-digestion of sludge. In addition, the washing wastewater may be significantly foamed due to the remaining detergent in the washing wastewater, and may overflow from the biological treatment tank 2 due to excessive aeration. Furthermore, although not limited to nuclear facilities, the capacity of the adjustment tank or mixing tank (Embodiment 3) may have to be reduced to minimize the installation area. Incidentally, in the biological treatment method, treatment performance is stabilized by avoiding load fluctuation as much as possible by continuous operation for 24 hours, and good treated water quality can be obtained. However, there is a case where the laundry wastewater needs to be treated in the biological treatment tank 2 within the time when the laundry wastewater flows, and rather, a countermeasure for low load in the time zone where the laundry wastewater 1 does not flow becomes a problem.

(Embodiment 5)
FIG. 5 is a view showing an improved example of the processing equipment shown in FIG. 1, 2, 3 or 4 for carrying out the processing method of the present invention, and in particular, shown in FIG. The improvement part for solving various problems in the processing equipment is extracted and shown. In FIG. 5, the laundry wastewater 1 flows into the biological treatment tank 2. A floating activated sludge floc is held in the biological treatment tank 2, and a flat membrane-like separation membrane 3, which may be the same as the separation membrane used in Embodiment 1, is immersed therein. Yes. In the biological treatment tank 2, a first air diffuser (first aeration means) 6a is installed immediately below the separation membrane 3, and a second air diffuser (second aeration means) 6b is installed at a position described later. The air diffusers 6a and 6b are supplied with air 5 from a blower (not shown) automatically or manually via valves 7a and 7b. The clear membrane filtrate 4 that has passed through the separation membrane 3 due to the difference in water level at the extraction position of the biological treatment tank 2 and the membrane filtrate 4 or pump suction flows out to the outside of the biological treatment tank 2 as treated water.

When filtration is performed by the separation membrane 3, the activated sludge and the washing waste water are aerated and mixed and air bubbles are washed on the surface of the separation membrane 3 by injecting air 5 from the blower from the diffuser pipe. Usually, the amount of air from 6a is preferably about 12 to 20 L / min per 1 m ² of membrane area. When the amount of air is less than about 12 L / min, the effect of cleaning the membrane surface is insufficient, and when it is more than about 20 L / min, not only is energy wasted, but vibration of the separation membrane 3 due to bubbles becomes excessive. , Membrane pain becomes severe and mechanical life is shortened.

  Moreover, the air supply to the separation membrane 3 can be performed intermittently. At this time, it goes without saying that membrane filtration is performed only when air is supplied. When the filtration by the separation membrane 3 is stopped, the valve 7a is closed to stop the air supply from the diffuser pipe 6a, and the valve 7b is opened to supply the air from the diffuser pipe 6b. These valves 7a and 7b can be opened or closed automatically or manually. The diffuser tube 6b added according to the present invention is preferably provided at a position where the bubbles discharged from the diffuser tube 6b and the resulting mixed liquid do not directly contact the separation membrane 3. When the membrane surface is bubble-washed when the valve 7a is closed and not filtered by the separation membrane 3, excessive vibration is applied to the joint surfaces of the members constituting the membrane module of the separation membrane 3 to shorten the mechanical life of the membrane module. This is because the adverse effect of doing this occurs.

  Moreover, it is preferable to supply the air from the diffuser 6b continuously or intermittently and adjust the amount of air so that the dissolved oxygen (DO) in the biological treatment tank 2 is about 1 to 6 mg / L. If dissolved oxygen (DO) is 1 mg / L or less, there is a risk that the activated sludge becomes anaerobic, and if it is continued at 6 mg / L or more for a long period of time, the activated sludge is fragmented and the clogging of the separation membrane 3 is accelerated. Become.

  In particular, washing drainage occurs only during the daytime (for example, 5-8 hours of day shift) and does not occur at all at night, and the above-described adjustment tank is not provided on the front side of the biological treatment tank 2, and washing is performed. The operation is performed so as not to contradict the above-described treatment method under the condition that the waste water must be treated during the time until it flows out of the biological treatment tank 2. That is, during the inflow time period of the laundry wastewater 1, filtration of the separation membrane 3 and continuous or intermittent aeration by the diffuser 6a are performed. Aeration by the trachea 6a is stopped, and aeration is continuously or intermittently performed by the aeration tube 6b.

  A small amount of radionuclide contained in the washing wastewater discharged from the nuclear facility treated in this way is retained in the activated sludge floc and is discharged as excess sludge to the outside of the biological treatment tank 2 in a timely manner (Fig. 1 to FIG. 4). In addition, the decontamination factor (radioactivity concentration in laundry wastewater / radioactivity concentration ratio in treated water) was about 20 or more in this modified example. As in the first to fourth embodiments, activated sludge floc is initially washed with sewage sludge and sludge used in industrial wastewater treatment as seed sludge and added with ammonium salts and phosphates as nutrient sources. Acclimate with drainage and grow until activated sludge concentration reaches about 6000 to 10000 mg / L. When the wastewater is treated, its concentration increases due to the proliferation of activated sludge, but usually the amount of excess sludge is withdrawn so as to be in the range of about 10,000 to 20000 mg / L (the excess sludge tank is not shown in FIG. 5). ). FIG. 5 shows a case where the biological treatment tank is a square tank and a diffuser tube 6b is provided at the lower part of the side wall on one side.

(Embodiment 6)
FIG. 6 is a diagram showing another improvement example of the processing facility described in FIG. 1, 2, 3 or 4 for carrying out the present invention, in which an improved portion is particularly extracted and shown. The difference from the example is that an air diffuser 6c and a valve 7c are added, and the installation position of the separation membrane 3 and the air diffuser 6a is at the center. The operation of the air diffuser 6c and the valve 7c is substantially the same as that of the air diffuser 6b and the valve 7b described in connection with the fifth embodiment.

  That is, FIG. 6 shows that when the biological treatment tank 2 is a square tank, the diffuser pipe 6b and the diffuser pipe 6c can be arranged near the lower portions of both side walls, and the biological treatment tank 2 is a circular tank. In this case, it is shown that the air diffuser 6b and the air diffuser 6c can be arranged concentrically near the lower part of the peripheral wall.

(Example 1 )
Washing wastewater discharged from the nuclear facility was treated with the treatment equipment partially shown in FIG. In this nuclear facility, laundry drainage occurred only for 8 hours during the day and did not occur for the remaining 16 hours. In addition, it was necessary to treat the generated wastewater for 8 hours when the wastewater was generated. The wastewater quality was COD 100 mg / L, SS 70 mg / L, and radioactivity concentration 2 × 10 ⁻³ Bq / mL. The COD volumetric load of the biological treatment tank 2 at this time was 0.3 kg / m ³ · d, and the activated sludge concentration was about 10,000 mg / L. The processing results are shown in Table 2.

As can be seen from Table 2, the quality of the treated water changed before and after the inflow of the wastewater, but both satisfied the discharge regulation value sufficiently. In addition, although not shown in FIG. 5, the treated water has pointed out the treated water which left the membrane filtration water tank 7 in embodiment of FIG. The shape of the biological treatment tank 2 was a square tank. The permeate flux did not fall below 0.6 m ³ / m ² · d even after half a year of operation.

(Example 2 )
Table 2 shows the results of treating the same laundry wastewater as used in Example 1 with the treatment facility shown in FIG. The shape of the membrane separation tank was a circular tank. The permeate flux did not fall below 0.6 m ³ / m ² · d even after half a year of operation.

It was treated with processing equipment 1 with the washing waste water of Example 1. As a result, the treated water had almost the same water quality as in Examples 1 and 2 , but the permeation flux decreased to 0.4 m ³ / m ² · d or less within 3 months of operation, confirming the improvement effect. It was.

  As described above, the treatment apparatus for washing wastewater from a nuclear facility according to the present invention aeration-mixes the washing wastewater discharged from the nuclear facility with activated sludge, and solid-liquid separates the obtained mixed liquid by a microfiltration membrane. Since it was made to do so, while being able to treat the washing drainage from a nuclear facility effectively, it is suitable for using for reducing radioactive waste significantly.

Is a system diagram showing an example of a treatment facility for implementing the processing method of the washing wastewater according to the first implementation. Is a system diagram showing an example of a treatment facility for implementing the processing method of the washing wastewater according to the second implementation. Is a system diagram showing an example of a treatment facility for implementing the processing method of the washing wastewater according to the third implementation. Is a system diagram showing an example of a treatment facility for implementing the processing method of the washing wastewater according to the fourth implementation. It is a systematic diagram which shows an example of the processing equipment which enforces the processing method of the washing waste_water | drain which concerns on Embodiment 5 of this invention. It is a systematic diagram which shows an example of the processing equipment which enforces the processing method of the washing waste_water | drain which concerns on Embodiment 6 of this invention.

Explanation of symbols

1 Laundry drain 2 Biological treatment tank 3 Separation membrane (microfiltration membrane)
4 Membrane filtered water 5 Air 6 Air diffuser 6a Air diffuser (first aeration means)
6b Air diffuser (second aeration means)
6c Air diffuser (second aeration means)
7 Membrane Filtration Water Tank 7a Valve 7b Valve 7c Valve 8 Treated Water 9 Excess Sludge 10 Excess Sludge Tank 11 Excess Sludge Pump 12 Dehydrator 13 Dehydrated Cake 14 Desorbed Liquid 15 Circulation Pump 16 Dry Air 17 Oxygen Enriched Membrane 18 Ozone Generator ( Ozone source)
19 Ozone 20 Ozone reaction tank (ozone source)
21 Mixing tank

Claims (7)

A biological treatment tank for aeration and mixing of laundry wastewater from a nuclear facility with activated sludge; a microfiltration membrane provided in the biological treatment tank for solid-liquid separation of the mixed liquid obtained by the aeration mixing; and the aeration mixing Therefore, the first aeration means provided immediately below the microfiltration membrane, the second aeration means provided at a position in the biological treatment tank where the generated bubbles do not contact the microfiltration membrane, and the microfiltration membrane A washing wastewater treatment apparatus comprising: a membrane filtration water tank that receives the membrane filtration water; and an excess sludge tank that receives excess sludge in the biological treatment tank.   A circulation pump that draws a part of the excess sludge from the excess sludge tank and returns it to the excess sludge tank; and an ozone reaction tank that is in communication with the circulation pump and disposed on the downstream side of the circulation pump. The processing apparatus of the washing waste_water | drain of Claim 1 which has communicated with the ozone source in the upstream.   The wastewater treatment apparatus according to claim 2, wherein about 0.04 to 0.08 kg of ozone is added to the surplus sludge from 1 kg of the surplus sludge from the ozone source.   A mixing tank that mixes the received cleaning wastewater with the desorption liquid and supplies the mixed wastewater to the biological treatment tank, a circulation pump that extracts a part of the activated sludge from the biological treatment tank and returns it to the mixing tank, and communicates with the circulation pump And an ozone reaction tank disposed downstream thereof, wherein the circulation pump communicates with an ozone source upstream thereof.   The wastewater treatment apparatus according to claim 4, wherein about 0.04 to 0.1 kg of ozone per kg of dry sludge is added to a part of the activated sludge from the ozone source.   The wastewater treatment apparatus according to claim 1, wherein hydrogen peroxide is added to the excess sludge tank.   The treatment apparatus for washing waste water according to claim 6, wherein an injection amount of the hydrogen peroxide solution is about 0.05 to 0.1 kg per 1 kg of dry surplus sludge.

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